Brake Drums

Older brake pads or shoes may contain asbestos, which has been determined to be cancer causing agent. Never clean the brake surfaces with compressed air! Avoid inhaling any dust from any brake surface! When cleaning brake surfaces, use a commercially available brake cleaning fluid.

Fig. Fig. 1: Many times it is necessary to retract the shoes slightly by turning the adjuster star (inside the brake drum) to remove the drum for inspection

Raise and safely support the vehicle.

Remove the rear wheels.

Remove the brake drum from the hub assembly by pulling the drum straight off the wheel studs.

If the drum is difficult to remove, remove the plug from the rear brake support plate. Push the self adjuster lever away from the star wheel using a thin screwdriver. The lever and star wheel are accessed through the hole on the rear brake support plate. Rotate the star wheel using a brake adjusting tool to retract the shoes.

Fig. Fig. 2: The brake drum is removed by pulling it straight off the wheel studs

Inspect the brake drum for thickness and runout. Replace or machine as necessary.

Inspect the brake drums for cracks, signs of overheating or excessive wear.

Measure the drum run-out and diameter. If not to specification, resurface the drum. Run-out should not exceed 0.006 inch (0.15mm). The diameter variation (oval shape) of the drum braking surface must not exceed 0.004 inch (0.090mm).

Fig. Fig. 3: Inspecting the brake drum inside diameter

Fig. Fig. 4: The maximum machining diameter is cast into the outer rim of the brake drum

Fig. Fig. 5: Use a wire brush to clean the outside of the brake drum to find the maximum diameter

All brake drums are marked with the maximum allowable brake drum diameter on the face of the drum.